There have been proposed various recording apparatuses for recording on recording medium such as paper, fabric, plastic sheet, OHP sheet, or the like. As for the methods employed by these recording apparatuses, the wire-dot method, thermal recording method, thermal transfer method, ink jet method, etc., have been proposed.
Among the abovementioned recording methods, the ink jet recording method which records on recording medium by jetting ink from nozzles disposed on a recording element makes it possible to form an image at a high level of density. It also makes it possible to record at a high speed while keeping the apparatus very low in noise. Further, an ink jet recording apparatus is advantageous in that it is low in operational cost, can be reduced in size, and can be used for recording in color with the use of multiple inks different in color.
For the reasons given above, an ink jet recording apparatus is used as an outputting means, that is, output terminal, for an information system, for example, a copying machine, a facsimile machine, an electronic typewriter, a word processor, a workstation, etc. Further, it is used as a portable printer for a personal computer, an optical disc apparatus, a video apparatus, etc. In other words, an ink jet recording apparatus can be modified in structure to accommodate the unique functions and usages of a system with which it is used.
Generally, an ink jet recording apparatus of the serial type is provided with: an ink jet recording head; a carriage on which the recording head is mounted; an ink container for supplying the recording head with ink; a conveying means for conveying recording medium; and a controlling means for controlling the preceding components. As for the types of ink jet recording head, there have been known those which use an electro-mechanical transducer element, such as a piezoelectric element, as the element for generating the energy for jetting ink, those which use an electro-thermal transducer element as the element for generating the energy for jetting ink, etc. Among those types of ink jet recording head, those which employ an electro-thermal transducer element are advantageous in that they are higher in the density at which nozzles can be disposed, are easier to reduce in size, and are lower in manufacturing cost.
When an ink jet recording apparatus of the serial type actually records on recording medium, it moves its recording head in the primary scan direction in a manner to scan the recording medium while jetting ink droplets from its nozzles. Further, it intermittently moves (conveys) the recording medium; it moves the recording medium in the direction perpendicular to the primary scan direction, by a distance equal to the recording width (at a preset pitch), when it is not actually recording. The recording head is provided with a large number of nozzles for jetting ink, which are arranged in the secondary scan direction. Thus, each time the recording head is moved in a manner to scan the recording medium in the primary direction, a part of an image, the width (in terms of secondary scan direction) of which corresponds to the nozzles count, is recorded.
An ink jet recording apparatus capable of recording in color employs multiple recording heads, which are different in the color of the ink they jet. Each recording head is connected to its own ink container, which contains the ink, the color of which matches the color to which the recording head is assigned. The ink containers, which are for supplying the corresponding recording heads with ink, are removably mountable in the main assembly of an image forming apparatus; each ink container is replaceable with a new one if it runs out of the ink therein. There are various ink containers; there have been known those which are made up of a pouch in which ink is stored, a connective portion for connecting an ink container with the main assembly of a recording apparatus, and a shell in which the pouch is disposed, those which are made up of a shell in which ink is directly stored, a connective portion attached to the shell, an air vent for allowing external air to enter the shell as the ink therein is consumed, and the like.
It is one of the extremely important matters for an ink jet recording apparatus that a correct ink container is properly mounted in the ink recording apparatus. That is, for the purpose of ensuring that an ink jet recording apparatus normally operates, it is extremely important that the ink in an ink container matches in color the ink which is to be jetted from a recording head to which the ink container is to be connected, and the connective portion of the ink container is properly connected to the ink receiving opening of the main assembly of the recording apparatus.
For the purpose of ensuring that an ink jet recording apparatus can be normally operated to obtain an excellent recorded image, it is also an extremely important matters that recording medium is accurately conveyed onto a platen in an ink jet recording apparatus, and the recording medium conveyance speed and recording medium conveyance direction in the recording apparatus are accurately controlled. That is, it is possible that recording medium is conveyed askew in an ink jet recording apparatus. If recording medium is conveyed askew in an ink jet recording apparatus, an image is recorded askew relative to the recording medium, and moreover, it is possible that the recording medium is caught, failing to be conveyed further, while it is conveyed onto, or moved on, platen; it is possible that paper jam, which has extremely adverse effects on the entirety of the apparatus, might occur. Therefore, in the field of an ink jet recording apparatus, it is desired to realize a compact ink jet recording apparatus which is low in cost, and yet, is capable of satisfying the above described requirements.
Japanese Laid-open Patent Application 10-230616 discloses an apparatus which uses an optical sensor to detect both the amount of ink remaining in an ink container and whether or not the ink container is present in the apparatus.
Japanese Laid-open Patent Application 2003-112430 discloses an ink jet recording apparatus, the main assembly of which is provided with a light emitting element for detecting whether or not an ink container is present in the apparatus, or whether or not the ink container is in the proper position in the apparatus.
Japanese Laid-open Patent Application 2003-266656 discloses an apparatus which optically detect the amount of the ink remaining in an ink container and is provided with a light emitting element which detects the type of the recording paper being conveyed, by illuminating the recording paper while the carriage is outside the area in which an ink container is mounted on the carriage.
However, the abovementioned ink jet recording apparatuses in accordance with the prior arts are not structured to simultaneously carry out the process of optically detecting the presence or absence of an ink container, the state of an ink container, or the like information regarding an ink container, and the process of detecting the state in which printing paper is being conveyed.